Toy vehicle track sets may include one or more track sections arranged to form a closed loop around which one or more toy vehicles can travel. The toy vehicles used in such closed loops may be either self-powered or receive power from an external source. Devices used to accelerate unpowered toy vehicles around a track are often referred to as “boosters.”
Boosters typically include one or more motor-driven rotating wheels adjacent to a portion of the track. As a vehicle passes through the portion of the track occupied by the booster, the rotating wheel temporarily engages the passing toy vehicle and accelerates the toy vehicle forward.
The most common type of booster includes a pair of spaced apart wheels on either side of the track. The pair of spaced apart wheels cooperate to simultaneously engage the passing toy vehicle from both sides.
Prior art booster wheels suffer from several problems. The most common type of booster wheel includes a disc-shaped member formed of a resilient foam material. Such a wheel may be prone to wear and may undesirably cup a passing vehicle from underneath, thus lifting the vehicle off the track. Furthermore, the foam may not be sufficiently deformable to accommodate wide toy vehicles.
A previous attempt to improve over a resilient foam booster wheel is described in U.S. Pat. No. 6,793,554. This patent describes a thin-walled booster wheel constructed from either plastic or rubber. The thin-walled booster wheel has improved wear resistance compared to foam booster wheels. However, under some operating conditions, the thin-walled booster wheel described in U.S. Pat. No. 6,793,554 may cup some toy vehicles from underneath, thus lifting such vehicles off the track.